Valves are often used to regulate the flow of pressurized fluid through a conduit, sometimes resulting in an adjustment of pressure between the environments separated by the valve. Such valves often incorporate the use of a diaphragm mechanism to actuate the valve. Accordingly, a pressure differential can be used to adjust the position of the valve, controlling flow of the fluid through the valve.
A spring, such as a compression spring, is often used to assist in positioning and actuation of the valve. For example, a spring can be used to provide a load on one side of a diaphragm to equalize the forces on the diaphragm and establish a closed state of a valve. Thereafter, a pressure differential can cause the diaphragm to flex, thereby adjusting the position of the valve.
In certain circumstances, however, the positioning of the valve in its conduit may be offset from a fully closed or fully opened position, which is desirable for calibrating the valve's responses. Because the valve is already positioned or installed, however, adjusting the position of one or more components in the valve assembly to change the open or closed state of the valve to its desired state can result in a change in extension or compression of the spring. Consequently, the performance characteristics of the valve can be altered due to the unaccounted-for pre-loading of the spring load against the diaphragm.